Wind energy is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal-Axis Wind Turbine (HAWT) or a Vertical-Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

Wind turbine design with emphasis on Darrieus concept Ion Paraschivoiu

\n Unacceptable environmental pollution from the fossil fuel energy sources is increasing the demands on green energy concept and developing alternative solutions and has encouraged the international community to employ clean and renewable energy sources such as wind energy. Among different types of wind turbines, Savonius vertical axis in spite of its fascinating advantages including low rotational speed and noise, self-start capability, and independency relative to wind direction has gained less attention in industry due to low energy conversion efficiency. This paper investigates the insertion of a one-way opening valve on the three-blade Savonius wind turbine to reduce generated negative torque on convex side of the blade. Position, size, opening direction, and the opening angle limitation are defined as design parameters and 17 different scenarios in five main categories based on these parameters are modeled, simulated, and analyzed. Concluding, unlimited counter-clockwise large valve in position III exhibits 14% improvement in performance, which is promising.

On the Performance Enhancement of the Three-Blade Savonius Wind Turbine Implementing Opening Valve

Increasing energy demand and environmental regulations around the world provide an adequate framework for developing methods of obtaining energy from renewable sources. Wind force is a resource with a high potential through which green energy can be obtained with no negative impact on the environment. Different turbine typologies have been developed, which can convert the wind force into mechanical and electrical energy through turbine rotational motion. Starting from the classic vertical-axis SAVONIUS rotor model, other models have been designed, which, according to the numerical studies and experimental test results, show higher performance parameters in operation. Such models present specific rotor blade geometries to achieve better operational results in terms of shaft torque and generated power. There are multiple research results from numerical analysis on virtual models or experimental tests that use rotor models in different constructive configurations aiming to improve operation performance. These research activities are related to the rotor blade number, the aspect and overlap ratio values, the blade profile geometry modification, the use of end plates connected to the rotor blades, curtain mounting solutions for directing the air flow on the active blade alone, and rotor constructive variants with deformable blades during operation. Some of the results obtained from the mentioned research activities are shown in this review for special rotor configurations whose performance results in terms of torque or power values are compared to the classical SAVONIUS model.

https://www.mdpi.com/1996-1073/14/7/1962/pdf

Review of Specific Performance Parameters of Vertical Wind Turbine Rotors Based on the SAVONIUS Type

Thermal characteristics of the dryer with rice husk double furnace - heat exchanger for smallholder scale drying

Biogas pressure produced in a period of 10 days is 0.001 kg on the 3rd day to 0.013 kg on the 10th day or equivalent to an average of 0.0013 kg / day, which in each day experiences a different increase. The raw materials used are 8 kg cow dung and 2 kg pineapple skin waste with a raw material ratio of 4: 1 and 10 liters of water are added mixed with EM4. In this study, the authors compared the biogas pressure produced from a mixture of raw materials from cow manure and pineapple peel waste with biogas produced from a mixture of raw materials from cow dung and water hyacinth. The research method used is literature review, interviews and then the data collected will be used to calculate the ratio of biogas pressure. From the results of the biogas pressure comparison it was found that the mixture of raw materials for cow dung and water hyacinth was more effective than biogas with raw materials for cow dung and pineapple skin waste with a fermentation process within 10 days.

http://openjurnal.unmuhpnk.ac.id/index.php/STek/article/download/1944/pdf

Analysis Of Biogas Pressure Based On Mass Variation Of Raw Material Using 150 L / Tank Digester Capacity

The rising costs for the fossil fuel based energy and concern over the environment have caused a resurgence of interest in anaerobic treatment and subsequent use of the biogas produced during the treatment of organic waste as fuel.  Biogas from cattle dung has become a potential renewable energy source for both domestic and commercial usage especially in Lombok. Unfortunetly, due to the presence of carbon dioxide (CO 2 ) and Hydrogen sulphide (H 2 S) in biogas, it has become extremely difficult to store and transport it effectively and has lower energy density. This paper presents the study in biogas purification by mean of absorbing the CO 2 gas using the NaOH solution. In addition, the biogas production process used in 3 (three) kinds of cattle dung from horses dung, cows dung and buffaloes dung by the composition of 1 kg of manure to 1 Liter of water. The results show that generated the largest volume on the composition of C with average volume reached 72.419 liters, then the composition B reached 61.794 liters, and the lowest in the composition of A with an average volume of 51.478 liters. The highest power generated in the treatment composition A with 2.5 N NaOH solution at 108.5 watts and the lowest power generated by the composition of C without treatment of 25.67 Watts.

/pdf/analisis-penyerapan-gas-karbondioksida-co2-dengan-larutan-2wq68sk8zb.pdf

Analisis Penyerapan Gas Karbondioksida (CO2) Dengan Larutan NaOH Terhadap Kualitas Biogas Kotoran Sapi

The wind turbine is a device that converts wind energy into mechanical energy and then converted into electrical energy through a generator. Horizontal axis wind turbines can increase the efficiency to get the maximum power coefficient. One was using the blade numerous. Maximum efisiensi system will increase the number of watts (power) generated so as to obtain a certain number of watts by simply using the number of windmills less The object of this research is the performance testing horizontal axis wind turbine with wind speed variation and variation in terms of the number of blade Efisiensi system ( 𝜂 ) and Tip Speed Ratio (TSR). Research conducted with the wind coming from the source to the Wind Tunnel fan to direct wind. Wind speed is used there are three variations of the 3 m/s, 3.5 m/s, and 4 m/s and varying the amount of blade that is 3, 4, 5 and 6 blade. The results showed that the best 𝜂 values obtained at a maximum wind speed of 4 m / s and the number of blade 5 with a value of 3 . 07 % 𝜂 , whereas 𝜂 smallest value obtained at wind speeds of 3 m/s and the number of blade 3 that the value of 0.05% 𝜂 . For TSR maximum value at a maximum speed of 4 m/s occurred in the number of blade 5 is equal to λ = 2.11, while the lowest value at wind speeds of 3 m/s resulting in blade number 3 is equal to λ = 1.49.

/pdf/pengaruh-kecepatan-angin-dan-variasi-jumlah-sudu-terhadap-z95bnz8yav.pdf

Pengaruh kecepatan angin dan variasi jumlah sudu terhadap unjuk kerja turbin angin poros horizontal

Utilization of rice husk biomass in the conventional corn dryer based on the heat exchanger pipes diameter

Savonius turbine is a type of vertical-axis wind turbines. The turbine has a potential to be developed as it has a simple construction and is suitable for low wind speeds. However, the turbine is still rarely used because of the low efficiency of the turbine compared to other turbines. The low efficiency of the turbine is due to the negative moment. Some efforts have been done to reduce the negative moment such as by adding a wind concentrator. The wind concentrator can steer the incoming wind toward the turbine blades that generate positive moments, consequently, the generated power increases. The aim of this research is to determine the effect of the number and diameter of the Savonius blade wind turbine with an additional concentrator. The concentrator had a concentration ratio of 6:1 and it was tested at the lower wind speeds of 2-5 m/s. The result shows that adding a wind concentrator can increase the rotational speed of the rotor, power coefficient, and the turbine power. The Savonius turbine with two blades has the best performance compared to the three and four blades. The Savonius blade wind turbine with the rotor diameter of 12 cm is the best Savonius turbine for the concentration ratio of 6:1.

/pdf/effect-of-concentrator-blade-diameter-and-blade-number-on-5dhwwpp012.pdf

I Made Mara

Papers

Analisis Penyerapan Gas Karbondioksida (CO2) Dengan Larutan NaOH Terhadap Kualitas Biogas Kotoran Sapi

Pengaruh kecepatan angin dan variasi jumlah sudu terhadap unjuk kerja turbin angin poros horizontal

Utilization of rice husk biomass in the conventional corn dryer based on the heat exchanger pipes diameter

Thermal characteristics of the dryer with rice husk double furnace - heat exchanger for smallholder scale drying

Effect of Concentrator, Blade Diameter and Blade Number on the Savonius Wind Turbine Performance